电针对大鼠吗啡条件性位置偏爱及腹内侧前额叶皮层谷氨酸能神经元激活的影响

目的:观察电针"足三里""三阴交"对吗啡成瘾大鼠条件性位置偏爱(CPP)及腹内侧前额叶皮层谷氨酸能神经元激活的影响,探讨针刺戒毒的中枢机制。方法:SD大鼠随机分为对照组、模型组、电针组,每组10只。大鼠进行吗啡CPP训练和测试(在偏爱箱给予大鼠腹腔注射吗啡10 mg/kg,连续3 d,非偏爱箱注射0.9%氯化钠溶液)。每日CPP训练前30 min以2 Hz/100 Hz电针大鼠"足三里""三阴交"20 min。实验第4天进行CPP测试。用Fos/谷氨酸囊泡转运体2(VGLUT2)荧光双标免疫组织化学法测定各组大鼠腹内侧前额叶皮层谷氨酸能神经元的表达,用多通道微阵列电生理系统测定腹内侧前额叶皮层放电频率和神经元激活情况。结果:与对照组比较,模型组大鼠吗啡CPP得分显著提高(P<0.01);腹内侧前额叶皮层Fos阳性细胞数、VGLUT2阳性细胞数及Fos/VGLUT2双标记阳性细胞增多(P<0.01,P<0.05)。与模型组比较,电针组大鼠吗啡CPP得分显著降低(P<0.01);腹内侧前额叶皮层Fos阳性细胞数、VGLUT2阳性细胞数及Fos/VGLUT2双标记阳性细胞减少(P<0.01,P<0.05);大鼠在偏爱箱/非偏爱箱的放电频率比值和激活神经元数量降低(P<0.001)。结论:电针抑制吗啡CPP行为可能与抑制腹内侧前额叶皮层谷氨酸能神经元的激活有关。

Effect of electroacupuncture on morphine-conditioned place preference and activation of glutamatergic neurons in the ventromedial prefrontal cortex in rats

Objective To observe the effect of electroacupuncture(EA)at"Zusanli"(ST36)and"Sanyinjiao"(SP6)on conditioned place preference(CPP)and activation of glutamatergic neurons in the ventromedial prefrontal cortex(VMPFC)of morphine-addiction rats,so as to explore its mechanisms underlying detoxification.Methods Thirty male SD rats were randomly and equally divided into control,model and EA groups.The rats with acquisition of morphine-induced CPP received intraperitoneal injection of morphine(10 mg/kg)in the morphine-paired chamber,once daily for 3 consecutive days,and those of the control group received intraperitoneal injection of the same dose of normal saline in saline-paired chamber.Thirty minutes before CPP acquisition training,EA(2 Hz/100 Hz,0.5 to 1.0 mA)was applied to ST36 and SP6 for 20 min every day.The double-labeled neurons of Fos/vesicular glutamate transporter 2(VGLUT2)in the VMPFC were detected by using fluorescent immunohistochemistry.The discharges of the VMPFC neurons were recorded by using a multi-channel microarray electrophysiological system,followed by performing a z-score standardized processing.The ratio of firing rate frequency of rats in the morphine-paired chamber/saline-paired chamber was calculated,and further statistical analysis was conducted on the data based on the standardized z-scores.The neuronal firing characteristic of glutamatergic neuron is low frequency and wide wave.Results Compared with the control group,the score of morphine-induced CPP and numbers of Fos,VGLUT2-positive and Fos-VGLUT2 double-labeled positive cells were significantly increased in the model group(P<0.01,P<0.05).After EA and in comparison with the model group,the morphine CPP score and numbers of Fos,VGLUT2-positive and Fos-VGLUT2 double-labeled cells were significantly reduced in the EA group(P<0.01,P<0.05).The ratio of firing rate of the VMPFC neurons in the preference chamber and the percentage of inhibitory neurons as well as the z-score were considerably lower in the EA group than in the model group(P<0.001).Conclusion EA can suppress morphine-induced seeking behavior in rats,which may be related to its inhibitory effect on glutamatergic neurons in the VMPFC.